Air heater



Oct. 19 1926. 1,603,960

A. T. LEWIS AIR HEATER Filed April 14, 1923 2 Sheets-Sheet l Oct. 191926. 1,603,960

A. T. LEWIS AIRHEATER 7 Filed April 14, 1923 2 Sheets-Sheet 2 %Z 3 Z6 Z425 /0 HVVENTOI? 2?; ::2 4Zexazza'er7Zarnfa2z Lewis,

ATTORNEY Patented Qct. 19, 1926.

' UNITED STATES 1,603,960 PATENT OFFICE! ALEXANDER THORNTON LEWIS, OFMERION, PENNSYLVANIA, ASSIGNOR T YORK,

HEATING AND VENTILATING CORPORATION, OF PHILADELPHIA, PENNSYLVANIA,

A CORPORATION OF PENNSYLVANIA.

AIR HEATER.

Application filed April 14, 1923. Serial No. 631,959.

Some of the objects of the present invention are to provide animprovement in unit I heaters; to provide an improved coil constructionfor heating a circulating medium;

to provide a heating unit in which there are no couplings or otherthreaded fittings; to provide an air heater of the unit. type whereinprovision is made for the free inlet of air from all" sides of theheater and causing the same to circulate in ,anefficient manner throughthe heater; toprovide an ar-.

rangement of heater coilswherein expansion and contraction can beautomatically com- 'pensated and without placing heater connectionsunder strain; to provide a unit heater wherein a natural circulation ofthe heated medium can take place; and to provide other improvements aswill hereinafter appear.

In the accompanying drawings, Fig. 1 represents a front elevatlon inpart section of a. unit heater embodying-one form of the presentinvention; Fig. 2 represents a side elevation, in part section, of thesame; Fig. 3 represents a detail in elevation of one form of heatercoil; Fig. 4 represents a top plan of the coil shown in Fig. 3 Fig. 5represents a detail in end elevation of the coil; and Fig. 6 representsadetail section of the pipe jointing.

Referring to the drawings, one form of the present invention comprises acasing 10 of general rectangular form which is open at its lower'end toprovide an inlet 11 for air or other medium, and is also open at itsupper end to provide an outlet '12 for the medium passing through thecasing. Preferably, the casing 10 is mounted on legs 13 so that theinlet 11 .is spaced from the floor line to allow the air to pass freelyinto the casing 10 from all sides.

In order to increase circulation of air or other medium through thecasing 10, a housing 14. is mounted upon the top of the casing lO andserves to support a rotatable fan 15 which is fixed to a shaft 16journalled in bearings 17 on the exterior of the housing to be out ofdirect contact with the heat.

The shaft 16 is driven by a pulley 18 from any suitable source of power.The housing 5 ,14 i s of openended construction so that its chamber 20becomes a' continuation of the chamber 21 formed by the casing 10'. Theoutletend of the housing 14 is preferably arranged to discharge into adistributing In the form shown the series of pipe coils 26 leads from'one side of the header 24 downwardly in a succession of loops 'to theopposite side of the header 25. The series of pipepoils 27 leads fromthe side of the header 2 L opposite to the'coils 26, downwardly in asuccession of loops to the opposite side of the header 25, but thearrangement of this series 27 is such that it has a staggered relation,as horizontally con sidered, with respect to the series 26. Each of thetwo series of coils is made up of a plurality of separate pipes whichare respectively bent to form parallel lengths connected by end loopsand the aforesaid lengths and loopsof each pipe lie in the same verticalplane. Thus, in assembled condition the series of coils 26 is arrangedin as many vertically disposed planes as there are pipes in the series,and likewise the series of coils 27 is arranged in as many verticallydisposed planes as there are pipes in the series. In assembled conditionthe coil structure 23 is made up of alternate sections of the two seriesof coils 26 and 27 arranged in abutting relation so that a tortuous pathfollowing a general vertical direction through the coils is providedbecause of the staggered relation of the pipe lengths which brings thehorizontal lengths of pipes of one series opposite the respective spacesbetween the horizontal lengths of the other series. This constructionprovides a maximum heat ing surface with whichthe air is brought intointimate contact without placing any abrupt obstruction in the path offlow of the air. Thus, with the heating medium entering byway of theheader 24: at the top of the housing and the air entering the inlet 11at the bottom of the housing, there is provided a highly eilicientcounter-current flow whereby the available heat is utilized withoutwaste.

As a means for attaching the ends of each pipe to the respective headers24 and 25 the latter are suitably drilled in vertically staggeredrelation at opposite sides thereof for proper spacing of the coils, andafter inserting the ends of the pipes in the respective drilled openingsthey are welded into place as indicated at 28 so that the entire heatingcoil structure becomes a unitary one without threaded joints, couplingsor other fittings ordinarily employed in coil construction. Thisconstruction practically eliminates leaking joints and connections,reduces repairs to a minimum, and makes the cost of maintenance so lowas to be negligible.

For'connecting the heating coils to a steam line or other source ofheat, the headers 24 and 25 project to one side of the casing 10 so thatconnections can be readily made for causing the heating medium tocirculate through the coils. Preferably also the headers 24 and 25 aretied together for strength 'ening purposes by tie bars 30 arranged atopposite sides of the coil structure and having their ends welded to therespective headers toform a rigid construction. Preferably also theheaders 24 and 25 are respectively supported and held properlypositioned within'the casing 10 by suitable straps 31 and 32, the endsof whieh have Welded connection with angle bar construction of thecasing. It will thus be evident that While the headers 24 and 25 arerigidly held by welded strap and tie-bar construction, the coilstructure 23 is free to expand or contract throughout its length with amovement somewhat simulating a bellows action though it is held fast atthe welded connection with the headers which are not subject to openingup and causing leaks as do the ordinary threaded coupling joints.

From the foregoing it will be apparent that a complete heating unitv hasbeen devised which is simple and operable in construction, economical inoperation, and adaptable to a variety of uses. A unit of this characteris an ideal heating means for foundries, machine shops and other exposedbuildings, and is also effectively employed to supply fresh heated airto rooms in which exhaust systems are used for removing dust fumes orchemical vapor. It has also been found highly eflicient in dispellingfog in .dye houses, paper mills, and packing houses where steam vapor isprevalent.

Attention is further directed to the welded construction of the coilends with the headers as this results in a thickening of the wall-of thepipe at the joints and gives reinforcement where in prior coilconstructions the joints have been weakened owing to the removal ofmaterial in cutting the threads for the joints.

While the construction here shown is a vertical type of heater it is tobe understood that this is only by way of example and the invention isnot'limited to any specific position or arrangement. Also while but asingle formis-shown in which the invention may be embodied, it is to beunderstood that the invention is not limited to any specificconstruction but might be applied in various forms without departingfrom the spirit of the invention or the scope of the appended claims.

Having thus described my invention, I claim:

1. In a unit heater, the combination with a casing having an air inletand an air outlet, of means for causing a circulationof air through saidcasing, and a coil heating structure supported within said casingcomprising two headers, tie bars rigidly holding said headers in spacedrelation, Welded means for supporting said headers in said casing, andtwo series of pipe coils forming a substantially flexible connectionbetween said headers, said series of coils lying respectively inparallel planes and the coils of one series being staggered horizontallywith respect tothe coils of the other series.

2. In a unit heater, the combination with a casing having an air inletand an air outlet, a housing secured to the top of said casing andcommunicating with said casing, a fan in said housing, means forrotating .said fan to produce a circulation of air through said casing,and a coil heating structure supported in .said casing comprising twoheaders spaced apart, two series of pipe coils connecting said headersand extending on opposite sides thereof, said series being staggeredhorizontally with respect to each other with the overlapping portionsarranged in substantially abutting relation and the end connections ofsaid series being staggered vertically on opposite sides of the headers.

3. In a unit heater, the combination with a casing having an air inletand an air outlet, of means for causing a circulation of air throughsaid casing, and a coil heating structure supported within said casingcomprising two headers, tie bars rigidly holding said headers in spacedrelation, and two Series of flexible connection -between said headers,said series of coils lying respectively in parallel planes and the coilsof one series being staggered horizontally with respect to the coils ofthe other series.

Signed at- Philadelphia, in the county of Philadelphia, State ofPennsylvania, this 11th day of April, 1923.

ALEXANDER THORNTON LEWIS.

pipe coils forming a substantially

